At a critical moment in the prevention and control of the new coronary pneumonia outbreak, a paper published in the New England Journal of Medicine has pushed the Centers for Disease Control and Prevention (CDC) to the forefront. The reason, according to the paper, shows that human-to-human transmission has occurred between close contacts since mid-December 2019. In addition, from January 1 st al-Jan to January 11, a total of seven medical staff were infected. But at this point, the public knows nothing about it.
(Original title: Gofu’s exclusive response to a fortune: we don’t see clearly, confusing the paper with clinical diagnosis)
Should scientists publish papers first or should they first conduct prevention and control? The focus of the controversy comes from this. In the early morning of January 31, the first financial reporter interviewed Gao Fu, a member of the National Health and Health Commission’s high-level expert group and director of the China Center for Disease Control and Prevention. He is a co-author of the above paper.
“This is a retrospective analysis!” Mid-December is not known what disease, the pathogen is not clear, are investigating more than 400 cases of epidemiological inference! Onset’s days are all speculation, this people do not see! Mix epidemiological investigations with clinical diagnosis. Gaofu said to First Finance.
Gao Fu also said that the retrospective investigation is one of the CDC’s responsibilities, to find the culprit, retrospective investigation, guide the future prevention and control. “Our prevention and control has not stopped, for a month no one sleep. “
This is retrospective analysis.
The paper, published on January 29th, U.S. time, was led by the China Center for Disease Control and Prevention, and included professionals from more than a dozen units, including the Hubei Provincial Center for Disease Control and Prevention and the University of Hong Kong. The study’s authors include Feng Zijian, deputy director of the China Center for Disease Control and Prevention, and Yang Bo, director of the Centers for Disease Control and Prevention in Hubei Province. The co-author also includes Gao Fu.
In this paper, the team analyzed 425 laboratory-confirmed cases reported as of 22 January 2020. The median age of the first 425 confirmed patients was 59 years, compared with 56% for men, the analysis showed. The majority of cases (55 per cent) that had occurred by 1 January 2020 were related to the Huananhai Wholesale Market, compared with 8.6 per cent of subsequent cases. The average incubation period is 5.2 days, and the 95th percentile of the distribution is 12.5 days. In the early stages, the case size of the epidemic doubles every 7.4 days, with an average continuous interval of 7.5 days for infection and an estimated 2.2 basic infections (R0).
Based on the information, the paper says there is evidence that human-to-human transmission has occurred between close contacts since mid-December 2019.
The paper has raised widespread doubts about the disclosure of more information about the outbreak of new coronary pneumonia.
On January 31, the CDC published an article entitled “Notes from the Chinese Center for Disease Control and Prevention on Articles Published in the New England Journal of Medicine”, which stated that the paper was based on a retrospective analysis of 425 confirmed cases (including 15 medical personnel) reported as of January 23, 2020. All cases were published to the public prior to the writing of the paper. The 15 medical personnel mentioned in the paper were reported to the public in the early hours of January 20th, respectively, by Zhong Nanshan, head of the high-level expert group of the National Health and Care Commission.
The paper’s view that “human-to-human transmission occurred in close contacts in December 2019” is based on retrospective inferences from 425 case epidemiological survey data.
The article also said that the timely publication of the results of the survey in academic journals will help professional colleagues at home and abroad to understand the characteristics of the disease in a timely manner, jointly assess and evaluate the epidemic, improve prevention and control strategies.
However, the article did not respond to the CDC’s judgment on when “human-to-human transmission occurred in December 2019 among close contacts.”
For infectious epidemiology, retrospective studies are indeed extremely important, without retrospective studies can not be more clearly aware of the incidence of infectious diseases, and then develop infectious disease prevention and control strategies. Therefore, after an outbreak of an infectious disease and the diagnosis of a case, the first to appear is the epidemiology investigators.
An epidemic virology expert also told reporters that retrospective research is the basis of infectious diseases, must be based on existing cases, in the absence of cases, no one can observe what the path of the virus development.
“In fact, the data of 425 cases are not enough to show the characteristics of the new virus, only to illustrate the past and (425 cases) of the situation, how the future will develop, need to continue to be observed.” The epidemic virology expert said.
As the CDC states, these cases are previously announced confirmed cases, and the team used the public data to begin a retrospective analysis.
How retrospective analysis unfolds
According to this paper, the earliest cases of new coronary pneumonia were determined by the “unexplained pneumonia” monitoring mechanism.
In order to identify cases of pneumonia and to increase sensitivity to early detection, the team developed a tailored surveillance program to identify potential cases by 3 January 2020.
The initial work case definition for suspected new coronary pneumonia is based first on sars and Mers case definitions. Following the obtaining of new information on confirmed cases, the epidemiological criteria for defining suspicious cases were updated on 18 January 2020.
Once suspicious cases are detected, a joint team of china CDC, provincial, local and municipal CDC and county CDC will be notified to conduct detailed on-site investigations and collect respiratory samples, which will be centrally tested at the CDC Virus Disease Prevention and Control Institute.
A joint team of CDC and local CDC staff also conducted detailed field surveys of all suspected and confirmed cases. They collectepidemiological data through interviews with infected persons, relatives, close contacts and health care providers to determine the history of exposure in the first two weeks of exposure, including the date, frequency, frequency and manner of exposure to wild animals, especially those available at the South China Seafood Market in Wuhan. In addition, the researchers collected information about exposure to any relevant environment, as well as contact with others with similar symptoms.
All epidemiological information collected in the survey, including the history of contacts, timelines and the identity of close contacts, was cross-checked.
With this path, the team obtained epidemiological information on 425 cases.
The basic infection is about 2.2
The important reason for the retrospective analysis of infectious epidemics lies in the fact that the laws of infectious diseases can only be seen clearly.
In addition to the above questioned content, this paper also revealed what interesting information?
In this paper, the researchers estimated the rate of outbreak growth by analyzing data on cases between December 10, 2019 and January 4, 2020.
The paper says the underlying infection of new coronary pneumonia is estimated to be about 2.2, limited to data made before January 4, meaning that the average patient will transmit the infection to 2.2 others. In the case of new coronary pneumonia, the paper says, control challenges include the apparent presence of many mild infections and limited resources to isolate cases and close contacts.
However, increased awareness of the outbreak and increased availability and utilization of inspections in recent weeks will increase the established rate of infection.
A chart used in this article shows a drop in the number of cases after 11 January. But the paper also says it is likely due to uncertainty about recent cases and delays in identification and reporting, rather than the true inflection point of morbidity.
Given that the availability and use of test kits will increase over time, the paper says extra care should be taken when explaining the rate of case growth in January.
Overall, the results also showed that the size of cases doubled every 7.4 days at an early stage. The average continuous interval is 7.5 days.
The paper also cautions that the next urgent step includes identifying the most effective control measures to reduce intracommunity communication. With a better understanding of epidemiological characteristics and the dynamic mechanisms of case attacks, there is also a need to improve the definition of work cases. At the same time, there is a need to continue to monitor cases to detect any changes in epidemiology, such as infection songroups of young people or health workers.